Re: [PATCH][RFC] Adding transition of CPU frequency countingsupport to perfcounters

From: Peter Zijlstra
Date: Sat Jul 18 2009 - 12:09:33 EST


On Sat, 2009-07-18 at 23:11 +0900, mitake@xxxxxxxxxxxxxxxxxxxxx wrote:
>
> Oh, my perf could count cpufreq events!
> Thanks for your nice advice!
>
> % perf stat -a sleep 60
>
> Performance counter stats for 'sleep 60':
>
> 479088.075595 task-clock-msecs # 7.984 CPUs
> 199080 context-switches # 0.000 M/sec
> 19584 CPU-migrations # 0.000 M/sec
> 322978 page-faults # 0.001 M/sec
> 29 cpufreq-up # 0.000 M/sec
> 42 cpufreq-down # 0.000 M/sec
> 73703367828 cycles # 153.841 M/sec
> 52005203450 instructions # 0.706 IPC
> 209762467 cache-references # 0.438 M/sec
> 84916856 cache-misses # 0.177 M/sec
>
> 60.009508200 seconds time elapsed
>
> And I'm using ondemand governor now,
> so kernel thread [kondemand] context causes freq transition.
> I didn't notice that...
>
> Could you merge this patch?
> Can I send this patch with descriptions and Signed-off-by?

Why, what is the usecase?

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